Find $ \left(5x^2+y\right)^2 $ using formula.

$$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$

where $ A = \color{blue}{ 5x^2 } $ and $ B = \color{red}{ y }$.

$$ \begin{aligned}\left(5x^2+y\right)^2 = \color{blue}{\left( 5x^2 \right)^2} +2 \cdot 5x^2 \cdot y + \color{red}{y^2} = 25x^4+10x^2y+y^2\end{aligned} $$

Divide both the top and bottom numbers by $ \color{orangered}{ 13 } $.

Multiply $ \dfrac{23}{12} $ by $ 25x^4+10x^2y+y^2 $ to get $ \dfrac{ 575x^4+230x^2y+23y^2 }{ 12 } $.

Step 1: Write $ 25x^4+10x^2y+y^2 $ as a fraction by putting $ \color{red}{ 1 } $ in the denominator.

Step 2: Multiply numerators and denominators.

Step 3: Simplify numerator and denominator.

$$ \begin{aligned} \frac{23}{12} \cdot 25x^4+10x^2y+y^2 & \xlongequal{\text{Step 1}} \frac{23}{12} \cdot \frac{25x^4+10x^2y+y^2}{\color{red}{1}} = \\[1ex] & \xlongequal{\text{Step 2}} \frac{ 23 \cdot \left( 25x^4+10x^2y+y^2 \right) }{ 12 \cdot 1 } \xlongequal{\text{Step 3}} \frac{ 575x^4+230x^2y+23y^2 }{ 12 } \end{aligned} $$